I think full sun is far too hot for JMs - especially reds. However, I'm no expert. I live in the Central Valley of California and I've lost a couple of very expensive maples because they got more sun than I realized.

Any JM would prefer some afternoon shade or filtered all-day sunlight but many are quite able to withstand full sun, provided they receive adequate irrigation. That really is the critical factor. And the red leafed forms tend to be the ones most often recommended for hot, full sun locations :-)

Both Pacific Coast Maples (located in Temecula, CA) andLakes Nursery (Newcastle, CA) have listings of sun tolerant JM's that include both Bloodgood, Emperor 1 and most of the red leaf dissectums.

Sounds like I need to plant more JMs - I have plenty of full sun spots! Full sun in the Central Valley, CA (zone 9) is FULL SUN. I sure would like to know which JMs could take that amount of light/heat. I would have to see it to believe it. :-)